The instant invention relates to a method of manufacturing a sealed, waterproof head assembly for a ruggedized LED flashlight. More specifically, this invention relates to a method of creating an internal sealing assembly that provides an integral and complete seal between the outer casing, lighting elements, and circuitry of the flashlight head. The flowable characteristics of the sealant and the manner in which the parts interfit create a unique structure not seen in the prior art.
Heretofore, the majority of flashlights utilized incandescent bulbs as a light source. The incandescent bulb was typically positioned within a cup reflector, which in turn was concentrically received within a threaded head ring. The outer end of the threaded ring included a clear acrylic cover to protect the incandescent bulb from damage while also allowing light from the bulb to project outwardly. The inner end of the head ring was inwardly threaded for receipt onto a complementary outward thread on the barrel of the flashlight housing. When waterproofing of the head was required, the manufacturers typically utilized compressible o-ring gaskets between the acrylic cover and the head ring, and also concentrically within the threaded connection. Threaded mounting of the head ring onto the barrel sufficiently compressed the cup reflector and acrylic cover against the head ring to provide waterproofing of the head assembly.
With the recent price reductions of super bright white light LED""s, there has been a push to incorporate these new LED""s into flashlight assemblies. In many cases, manufacturers are simply creating new bulb assemblies using a single LED or multiple LED""s. These assemblies are known as based LED""s. They include appropriate circuitry for voltage control and can be threaded into the same sockets as a conventional incandescent bulb. The manufacturer simply installs the based LED assembly into the old flashlight assembly. In this manner, no modifications of the flashlight head or housing are required.
However, the light emitted from these based LED assemblies is not ideal because LED""s have a different light emission pattern that does not reflect correctly off of the cup reflector. While retrofit based LED""s have bridged the gap in introduction of LED""s into flashlights, there are drawbacks to this retrofit approach as noted above. Accordingly, there is perceived to be a need in the art for an entirely new head assembly specifically engineered for the physical constraints of the LED package as well as the optical needs of LED semiconductor light source.
In this regard, and in furtherance of the above stated objectives, the present invention provides a novel method of manufacturing a waterproof head assembly specifically designed for LED light sources. The method is necessitated by several novel conditions that arise with LED flashlight devices. The first novel design aspect of the head assembly is that the LED""s are not enclosed behind an acrylic cover. LED""s are ruggedly packaged and not susceptible to the same type of damage, as would an incandescent bulb. Accordingly, the rounded end surface of the LED package need not be protected within an enclosure. The rounded end surfaces of the LED are thus exposed to the outside environment through apertures formed in a solid end wall of the head assembly. In this regard, the apertures in the end wall now provide an entry point for unwanted fluid contaminants, i.e. water, into the interior of the flashlight. The second novel design aspect of the present head assembly comes from a need to compensate for this new entry point. To prevent water from entering into the interior of the flashlight through the apertures, the applicant has filled the interior cavity of the head with a sealant which substantially entirely fills all of the gaps between the outside surfaces of the LED""s, the inside surfaces of the apertures, and the inside surfaces of the open end of the head assembly.
More specifically, the sealed head assembly comprises a tubular enclosure including a tubular sidewall, and an end wall, wherein the inner surfaces of the end wall and the sidewall cooperate to define an open end of said enclosure. The end wall includes a plurality of inwardly extending apertures for receiving the LED""s therein. The head assembly further comprised a circuit board (mounting board), which is snugly received in intermitting engagement within the inner sidewalls of the open end of the enclosure. In this regard, the inner or upper surface of circuit board and the inner surfaces of the sidewall and the end wall cooperate to define a substantially enclosed interior cavity within the tubular enclosure. A plurality of LED""s are mounted on the inner surface of the circuit board in electrical communication with contact leads on the circuit board. When the circuit board is received in interfitting engagement within the sidewalls of the enclosure, the LED""s are in turn slideably received within the corresponding plurality of apertures in the end wall. Finally, to prevent water or such other fluid contaminant from entering into the flashlight through the open apertures, a sealant is injected into the enclosed interior cavity through a hole in the circuit board so as to substantially entirely fill the enclosed interior cavity.
It is therefore an object of the present invention to provide a method of manufacturing a sealed head assembly for an LED light wherein the LED lighting elements are exposed to the outside environment. It is another object of the invention to provide a method whereby a sealed head assembly for an LED light, which includes a minimal number of parts that is simple to assemble for mass production. It is a further object of the present invention to provide a method of sealing a flashlight head that has improved performance characteristics, such an internally formed and protected seal that is not exposed to normal wear. It is yet another object of the present invention to provide method of sealing an in-line flashlight assembly that is completely enclosed within the body of a flashlight thereby eliminating the possibility of contamination and damage from external forces.
Other objects, features, operational details and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.